Workpiece holding method

Abstract

It is an object of the present invention to provide a workpiece holding method which enables a workpiece to be held when a multi-fingered hand is used to grasp the workpiece that is in an untidy heap, even if a target workpiece is subject to interference from another workpiece, and thereby the method enhances the success rate for holding the workpiece. A workpiece holding method, when two holding devices (first to fourth fingers F1 to F4) are used to hold a workpiece (reinforcement W), including a unilateral holding process of inserting a first holding device (the first finger F1 and the second finger F2) at one holding device insert position (region A) to hold and lift a workpiece-to-be-held (reinforcement-to-be-held T) in a state where the workpiece-to-be-held has no interference from any other workpieces at the region A, and a bilateral holding process of inserting a second holding device (the third finger F3 and the fourth finger F4) around (region D) the workpiece-to-be-held lifted by the first holding device, to hold the workpiece-to-be-held.

Description

[0001]This application is based on and claims the benefit of priority from Japanese Patent Application No. 2010-103102 filed on Apr. 28, 2010, the content of which is incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a workpiece holding method, and more particularly to a method of holding a plurality of workpieces in an untidy heap using two holding devices.[0004]2. Related Art[0005]Conventionally, mechanical products such as vehicles are manufactured by assembling a number of parts. More specifically, for example, a plurality of robots are provided on a production line, a vehicle body or the like is conveyed along the production line, and a box-shaped bucket (pallet) containing workpieces (assembly parts) to be attached to the vehicle or the like are supplied to each of the robots. Each of the robots utilizes fingers of a hand provided at the end thereof to carry out an operation such as holding a workp...

AI Technical Summary

Benefits of technology

[0008]The present invention is conceived in view of the above problem, and it is an object of the present invention to provide a workpiece holding method that enables a target workpiece-to-be-held even if another workpiece is piled on top of the target workpiece, and thereby enhances the success rate for holding workpieces in an untidy heap, where a multi-fingered hand is used to hold workpieces in an untidy heap.

[0013]By lifting one end of the workpiece-to-be-held, an intermediate point thereof is proportionally lifted pivoting on the other end thereof. In this way, even if there has been interference from another workpiece at another holding device insert position thereof before lifting, such interference is eliminated, and there are no other workpieces that interrupt the insertion of the second holding device around the workpiece-to-be-held. In this state, it becomes possible to insert the second holding device around the workpiece-to-be-held and to hold the entire workpiece-to-be-held (bilateral holding process).

[0014]Thus, when a multi-fingered hand is used to grasp a workpiece from an untidy heap, in a state were another workpiece is piled on top of the workpiece-to-be-held, one holding device is inserted at one holding device insert position, at which the target workpiece has no interference from any other workpieces, to hold and lift the workpiece-to-be-held. In this way, the interference from the other workpiece at the other holding device insert position is eliminated. As a result, it becomes possible to hold the workpiece-to-be-held even if there has been interference from another workpiece at another holding device insert position thereof before lifting. As a result thereof, it is possible to increase the number of patterns of extracting a workpiece from among workpieces piled up in an untidy heap, and accordingly, to enhance the success rate of grasping a workpiece from among workpieces piled up in an untidy heap.

[0017]By lifting one end of the workpiece-to-be-held, the intermediate point thereof is proportionally lifted, pivoting on the other end thereof. With this, the interference from another workpiece at another holding device insert position thereof before lifting is eliminated, and there are no other workpieces that interrupt the insertion of the second holding device around the workpiece-to-be-held. In this state, it becomes possible to insert the second holding device around the workpiece-to-be-held and to hold the entire workpiece-to-be-held (bilateral holding process).

[0018]Thus, when a multi-fingered hand is to grasp a workpiece from an untidy heap, in a state where another workpiece is piled on top of the workpiece-to-be-held, with no interference from any other workpieces at one holding device insert position thereof, where one holding device is to be inserted, but with interference from another workpiece at another holding device insert position thereof, it is possible to grasp the workpiece-to-be-held even in such a state. Therefore, it is possible to increase the number of ways of extracting from among workpieces in an untidy heap and to enhance the success rate of grasping a workpiece in an untidy heap.

[0019]According to the present invention, when a multi-fingered hand is to grasp a workpiece in an untidy heap, it is possible to provide a workpiece holding method that enables grasping of a workpiece even if another workpiece is piled on top of the target workpiece and to enhance the success rate of grasping the workpiece in an untidy heap.

Problems solved by technology

Some workpieces such as sashes, molds, garnishings, and reinforcements have an elongated shape, and it is not always easy to hold such workpieces depending on their form or gravity center position thereof.

However, workpieces to be supplied to a robot may be contained in a bucket in a state where they are piled up in an untidy heap.

However, if another workpiece is piled on top of the target workpiece that is to be held, a problem may arise in that, even if one pair of the fingers can grasp the target workpiece, the other pair of the fingers may fail to grasp the target workpiece due to the interference of the other workpiece, thereby causing the target workpiece to be dropped.

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